Vibratory screen



. April 7, 1942. A. 'r. CECIL 2,279,225

' vIBRAToRY SCREEN Filed Dec. 2a, 1938 2 shetsl-sheet 1 [/VVENTOR ALEX I. CECIL,

BY OKMJVLM,

ATr'x A ril 7,1942. A.(T. CECIL I .VIBRATORY SCREEN 4 "Filed Dec. 28, 1938 '2 sheets-s eet 2 f/yvE/vToR 4 ALEX T. CECIL,

. BY 6K 77] ,flwn

A TT'X Patented Apr. 7, 1942 j. UNITED sTATEs, PATENT OFFICE 2,279,225 7 VIBRATORY-SCREENY Alex T. Cecil, Columbus, Ohio, assignor to The Traylor Vibrator Company, a corporation of Colorado Application December 28, 1938, Serial 'No. 248,054

7 Claims.

This invention relates to a vibratory screen and more particularly to such a screen including tappers which co-operate with the screen cloth to prevent blinding.

An object of the invention therefore is to proscreen.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a side elevational view of a vibratory screen comprising my invention;

Fig. 2 is a front elevational viewof the screen ofFig.l;

Fig. 3 is a transverse sectional view taken on the line 33 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is an enlarged sectional elevationalview taken on the line 44 of Fig. 3, looking in the direction of the arrows; and

Fig. 5 is a perspective view of a tapper comprising one aspect of my invention.

It has been found in practice that certain materials particularly when in a very finely ground state, examples of which are finely ground bauxite, alum and silicate sand, tend to blind or clog the screen cloth of a vibratory screen. I have provided an improved type of screen and tapper mechanism which in practice has been found very efiicient in eliminating this blinding action.

Referring particularly to Figs. 1 and 2 of the drawings there is illustrated a vibratory screen incorporating the features of my invention which in general takes the form of the screen disclosed in more complete detail in the patent to James A. Flint, No. 2,137,753, dated November 22, 1938, for a Vibratory screening device, to which reference is made for a more complete disclosure of the screen, except, however, that the screen of the abovementioned patent is a double deck reaction type screen, while that of the instant application is a single deck direct action type screen which makes for certain differences which are obvious and which will be evident from the following description of the screen of the instant application.

Said screen comprises a deck or frame lfl which is rigidly attached to and vibrated by a vibratory electro-magnetic motor I I. The deck I0 is formed by a pair of spaced side walls I2, I 2 which are interconnected by a plurality of transversely extending Z-shaped supporting bars I3 which are progressively so formed that the screen wire cloth I4 which isstretched across them, is arched. The side walls l2 of the deck II] are reinformed by channel members l5 which impart rigidity to said deck, which deck is rigidly attached to a cross-head l6 formed as an integral part of an armature shaft ll of the motor II, the center of which armature shaft I1 is clamped to a plurality of stacked spring bars [8 the outer ends of which are rigidly clamped in a main frame cast ing l9;

At its upper end the armature shaft l1 carries a bracket 20 to which is attached a laminated armature 2| positioned adjacent a field structure 22 comprising a U-shaped laminated core and field windings, which field structure 22 is adjustably supported by adjusting bolts 23 in a pair of spaced U-shaped brackets 24, the lower ends of which are rigidly attached to the main frame casting, 19. By energizing the field structure 22 with alternating or'mixed current, the armature 2| will be attracted and released periodically, to

attached to the two sides of the deck I0 to the center of which cross bar support a superstructure hang rod 28 is supplied.

The screen cloth I4 is rigidly attached to the deck' ID by a forward attaching cylinder 29 and adjustable attaching means 30'. The manner of attaching said screen cloth is disclosed in full detail in the above mentioned patent to James A.

Flint, as is the detailed structure of the vibratory motor. 7

Briefly described, the attaching means 30 includes a rotatable cylinder 36 extending across the deck frame I0 and received in semi-cylindrical bearings formed thereon. The cylinder has appropriate attaching rods which hook into a curved plate clamped or otherwise attached to the screen cloth [4, The outer ends of cylinder 36 have attached thereto arms 31 having their free ends bifurcated and notched to receive welding. I

trunnion nuts 38 through which thread adjusting screws 39 having adjusting heads 40 and sliding through resting bases 4| resting on brackets 42 carried by deck In, between which heads 40 and bases 4| are springs 43. By adjusting heads 40, arms 31 may be swung to rotate cylinder. 36 thereby to tension screen cloth M. To prevent the .blinding of the screen cloth 1 whenever fine material is being screened, particularly of the type above mentioned, the screen cloth I4 is tensioned to a lesser extent than .is. a

" supporting bar I3.

customary with screens of this type, such for example as the screen shown in the abovemene;

action of the screen cloth l4 would destroy its to insure against blinding of the screen cloth [4. The screen cloth in whipping is held against the soft rubber cap or strip 33 and thus will not be damaged but will effect the desired action which prevents blinding as aforementioned.

The rubber strip 34 provides a resilient nonmetallic support for each tapper 3| on each supporting bar I3 and prevents a metal-to-metal contact, thereby to prevent wear on either and to reduce the noise incident to the relative mo- ..tion between the channel member 32 and the During operation, the com- 'ponent of motion at right angles to the deck l0 screen cloth l4. The permitting of this whipping life in a short time unless some particular means is provided to prevent such destruction. 1 have provided such means, which means at the same time acts as a tapper to tap the screen cloth during' its vibration'or "whipping action. to .aid the Whipping action of the screen in the prevention of blinding thereof. I a

Referring particularly to Figs. 3, 4 and'5 of the drawings, it will be seen that thereis interposed between the top of each supporting bar l3 and the screen cloth, a tapper'3l. Each of said tappers 3! comprises a metal plate preferably in the form of aninverted channel 32,the topof which is covered with a; cap or strip 33 of resilient material, such. as soft rubber. Intermediate the downwardly extending flangesof the channel32 isa' strip 34 of resilient non-metallicmaterial which is preferably hard rubber. It is preferred that the strips 33 and 34 .be rigidly attached to the channel member 32 and in practice I have done this by molding the rubber 33 :and 34 directly ,to said channel-'32, which has been found to be very satisfactory and insures a permanent bond v betweenthe channel 32 and strips 33, and34.

Each tapper 3| is supp orted for vibration on tends to vibrate the tapping devices 3| relatively to the-deck l0 andatright angles thereto to separate periodically .the tops of cross supports l3 and the hard'rubber strips 34, the soft rubber strips 33 substantially always remaining in contact .Withthe under side of the screen cloth l4. It will thus be seen that the screen cloth may always be maintained in rched formation and stretched to-exert a -.desired--pressing downforce on the rubber cushion 33 to returnthe tappers 3| to their initial positions relative to. the supports l3of deck frame Ill. The longitudinal edges of the screen cloth. t4 are free. to permit a slight whippingaction..,asa whole relatively to the deck frame Hl butit is desired to restrict this whipping action toa small amount and rely on a supporting bar. l3 and preferably is mounted thereon as by friction attaching spring clips 35,

the upper ends of which ,are rigidly attached to the channel .32 as by welding. It is manifest that a tapper 3| may bereadily supported ona supporting .bar -I3 by beinglslipped thereover with the attaching clips in contact with said supporting bar l3. It is thusevident that the plate or channel 32 is resiliently supported upon the supporting bar l3 by virtue of the rubber strip 34,

and that the screen cloth I 4 is resiliently supported upon the cap or strip 33 of soft rubber. It

may additionally be pointed out that the deck' l0 is reinforced by a pair of longitudinally extendcommon with screens of this general type, to permit a certainamount of whipping action thereofriuring vibration of the deck II]. This whipping. action .of the screen cloth I4 is augmented 1 bylthe tapping. action of the tappers 3|, of which there is one onjeach ofthe supporting bars 13, 75

vibrations of the tappers 3| relatively to the deck frame t'o' secure the tapping actionf t o jar the screen cloth [4 sufiiciently toshakeout therefrom the fine particles of material that tend to clog or blindflthe' screen because" of the difiiculty they have in passing through the screen cloth. It should b e particularly noted-that the efficiency of operation ofnthe screen is maintained by the automatic tapping action. over a; wide area thereof extending entirely acrossfthe latter and distributed at intervals along 'thelatter longitudinally. Furthermore, the 'wear, on the screen cloth where the tapperscontact therewith is reduced to a minimum by the soft rubber strips 33. M It is thusevident thatI have provided a relatively simple andefficient tapper. toicooperate restricted: to the preciseconstruction herein disclosed. n x

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United ,States is:

1. In a vibratory screen, the combination with a deck frame comprising spaced-apartside walls interconnected by a transversely extending supporting bar, of a motor connected tosaiddeck frame tovibrate the'same, a screen cloth on said frame, means for adjustably tensioning said screen cloth,, and, tapper means comprising a 'metal member having a face of resilient material in contact with said screen cloth, said metal member being mounted on said bar for automaticjvertical tapper movement relatively to the latter, during operation of the-vibratory screen. 2. In a vibratoryscre'en, the combination with a'frame comprising a cross-piece, of motor means connected to said frame to vibrate the same, a screen cloth, means for supporting'said screen cloth on said frame to form a deck, and a tapper loosely supported on said cross-piece between said cross-piece and said screen and vibratable up and down relatively to said cross-piece, said tapper comprising a plate with cushioning material on one side in contact with said screen cloth and with hard rubber on the other side in contact with said cross-piece, the construction and arrangement being such that when said motor means operates to vibrate the said deck the said tapper will be automatically vibrated relatively to said cross-piece to prevent blinding of the screen cloth.

3. In vibratory mechanism, the combination with a frame, of a screen cloth, means for supporting said screen cloth on said frame, motor means connected to said frame to vibrate the same, a rigid member resting on said supporting means with its ends unattached thereto to enable said rigid member from end to end to vibrate freely up and down relatively to said supporting means, and a rubber buffer with its ends free from said supporting means but mounted between said rigid member and said screen cloth.

4. In vibratory screening apparatus, the combination with a frame, of a screen cloth mounted thereon to form a deck, means for vibrating said frame, a metal device mounted on said frame in fixed relation thereto except for a limited vibration relatively thereto, and a relatively narrow elongated member positioned to be compressed between said metal device and said screen cloth during operation of the screening apparatus, the contact of said elongated member with the screen cloth being maintained over a predetermined area.

5. In vibratory screening apparatus, the combination with a frame comprising a cross-piece, of means for vibrating the same, a screen cloth, mechanism for supporting said screen cloth on said frame to vibrate therewith, an elongated member mounted on said cross-piece to extend along the 'same for vibratory movement transversely thereof, a hard rubber buffer between said elongated member and said cross-piece, and a soft rubber buffer between said elongated member and said screen cloth.

6. In vibratory screening apparatus, the combination with a frame comprising a plurality of spaced-apart cross-pieces, motor means connected to said frame to vibrate the same, a screen cloth mounted on said frame and extending over said cross-pieces to form a deck, and a plurality of tappers mounted respectively on a plurality of said cross-pieces between each of said cross-pieces and said screen cloth, each tapper having its ends free and unattached and each tapper being free to vibrate throughout its length relatively to the cross piece to which it is connected when he motor means is operated.

'7. In vibratory screen apparatus, the combination with a frame comprising a plurality of crosssuppcrts distributed longitudinally along the frame, means for vibrating said frame, a screen, mechanism for supporting said screen on said frame for vibration therewith, and a plurality of tapping devices each free and unattached at its ends and each contacting with the bottom of said screen and respectively mounted on said crosssupports each for vibration relatively thereto and each extending across substantially the entire width of said screen, the distribution of the freeended tapping devices being over a Wide area both longitudinally and laterally of the bottom of said screen.

ALEX T. CECIL. 

